Various wireless communication devices and platforms are available today to allow users of such devices to access different at-times interrelated communication networks to wirelessly exchange voice and data communications over such networks. Common wireless data communication networks may include, but are not limited to, various cellular and Wi-Fi network technologies, which will be readily known by the skilled artisan. Upon connection to one of these networks, a mobile device will be assigned a network address or number and provided with various means to exchange voice and/or data over such network connection using this assigned network address or number. For example, mobile devices may exchange voice and text-based (e.g. SMS) communications over standard mobile telephony network, and/or exchange various data communications such e-mail, text messaging, multimedia messaging, and voice-over-data communications over standard mobile data network platforms. Likewise, a mobile device may be configured to exchange data communications over a wireless data network such as a home or public Wi-Fi connection to an ISP and thus circumvent higher costs generally associated with mobile data communications.
As a mobile device migrates from one cell to another in a same cellular network, voice and data communications may be handed over from one cell to the other in providing more or less continuous service to the mobile user. Generally, the mobile device will continuously probe reception quality from two or more base stations and, upon identifying that a better quality signal may be available from a new base station, the mobile device will negotiate with the new base station to have ongoing mobile communications handed over thereto from a current base station. As both base stations form part of the same mobile communication network, mobile communications can be more or less seamlessly transferred between a given mobile operator's various base stations as the mobile device changes location within the mobile operator's network. Likewise, a VoIP call can be maintained on a mobile device as the device is moved across a Wireless Local-Area Network (WLAN) or the like in which each wireless router shares a same Service Set Identifier (SSID), for example.
For most mobile data exchanges, such as text-based or multimedia messaging, emails, and Web browsing, a mobile device can also be configured to automatically switch between data networks with little to no service interruption. For example, a mobile device that is actively used to browse the Web or exchange emails over a mobile data network may automatically identify and connect to an available Wi-Fi connection and seamlessly transfer execution of data transactions from the mobile data network to the Wi-Fi data network, in some configurations, even within the context of an ongoing session. Given standard protocols used in such data transactions, such a TCP/IP, any lost or undelivered data package during the transition will be resent or otherwise addressed in subsequent communications with the mobile device's new IP address (e.g. Wi-Fi Access Point IP Address).
Unfortunately, seamless voice data migrations from one mobile operator's network to another data network are not so readily achievable. Namely, as voice data communications are generally established through a series of standard call setup procedures (e.g. call signaling and media initialization protocols), an established voice data call cannot readily be switched from one data network to another without call re-initialization.
For example, a VoIP (Voice over Internet Protocol) call is generally setup via a signaling protocol (e.g. SIP, H.323, SCCP, etc.), which is followed by a media (i.e. audio) setup for the call that is generally is negotiated via SDP (Session Description Protocol) to describe media initialization parameters. The SDP is used to describe the capacity of each call end point, namely the codec(s) each end can support and to which IP address and port inbound media is to be sent to. Accordingly, each call party exchanges SDP information at the beginning of the call and agrees on the codec and the respective IP addresses to be used during for the call. In some instances, new SDP information must be sent at the establishment of a call to accommodate an end point that may not be configured to support a specific codec and where transcoding is therefore necessary to establish communications between the two call parties. This is typically called a Re-Invite where both ends agree to a new SDP. However, if one of the IP addresses negotiated via the original SDP changes to a new IP address during an established call, the connection will be invariably lost as the other party's device will have no means to identify and readdress outbound communications to this new IP address. Accordingly, a new SDP must be invoked if media (e.g. Real Time Protocol or RTP media) is to be exchanged with a new IP address. In the context of a VoIP application running on a smartphone device or the like, the user must either complete an ongoing VoIP call over the originating network on which the call was initialized and established, or reinitialize the call upon accessing a new data network (e.g. when wishing to switch from a mobile data network to a local Wi-Fi network).
Mobile communications such as mobile voice-over-data exchanges can also be subject to variations in call quality due to various parameters, such as signal strength, data packet latency, speed, losses and variable rates resulting in oft times imperceptible, but occasionally significantly disruptive call quality degradation. While traditional mobile devices are provided with a signal strength indicator to reflect a signal strength from a nearest mobile network transmitter, little detail is made available to the user of such mobile device, and even less so to the mobile operator, as to actual call quality at either end of a mobile-initiated and/or terminated voice data call. Furthermore, perturbations in call quality during an ongoing call can generally frustrate participating parties who are left to question the source of the call quality degradations, and even wonder whether a call remains in effect or has been entirely dropped, and when.
This background information is provided to reveal information believed by the applicant to be of possible relevance. No admission is necessarily intended, nor should be construed, that any of the preceding information constitutes prior art.